Method and apparatus for threading closure caps



y 1968 H. A. SYEEMAN 3,382,699

METHOD AND APPARATUS FOR THREADING CLOSURE CAPS Filed March 11, 1965 '5 Sheets-Sheet 1 [720572, f emzazzZ 566mm,

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May 14, 1968 H. A. SEEMAN 3,382,699

METHOD AND APPARATUS FOR THREADING CLOSURE CAPS Filed March 11, 1965 3 Sheets-Sheet 5 United States Patent 3,382,699 METHOD AND APPARATUS FOR THREADING CLOSURE CAPS Herman A. Seeman, Lombard, Ill., assignor to Continenta! Can Company, Inc., New York, N.Y., a corporation of New York Filed Mar. 11, 1965, Ser. No. 438,916 13 Claims. (Cl. 72--355) ABSTRACT 0F THE DISCLOSURE A method and apparatus for threading a closure cap or other thin walled annular member made of pressure deformable material, the apparatus comprising a threading tool having cam actuated segments mounted in radial slots in a holder with coil spring elements seated on the peripheral surfaces of the segments which spring elements have a contour corresponding to the contour of the thread desired, which expand outwardly upon outward movement of the segments, and which bridge the spaces between the segments resulting from the outward movement thereof in radial paths so that when the tool is positioned in a cap, for example, and the segments are forced outwardly the spring elements will expand radially and produce a thread formation in the wall of the skirt which is continuous and without any interrupted portions.

This invention relates particularly to metallic closures for receptacles such as bottles and jars and it is more particularly concerned with improvements in a method and apparatus for fabricating screw-on type closures.

A general object of the invention is to provide a closure formed from sheet material bent into suitable shape to form a cap and provided with interior thread formations so that it is adapted for use with an ordinary screw thread finish on jars, bottles and like containers.

A more specific object of the invention is to provide an improved method and apparatus for threading the interior wall of a closure cap wherein each thread formation is continuous and uninterrupted from one end to the other.

A still more specific object of the invention is to provide a method and apparatus for threading the interior wall of a closure cap which results in thread formations of a uniform character each extending continuously and without interruption from the lead end to the terminal end thereof and which is applicable to the formation of caps with single or multiple start threads.

A further more specific object of the invention is to provide an improved method and apparatus for forming closure caps having interior and exterior side walls with continuous screw threads formed in the interior wall in such a manner that the outer wall and the lower edge of the cap is left smooth and free from any mark or indentation resulting from the threading operation.

Another object of the invention is to provide a method and apparatus for forming a closure cap with a top wall forming panel and an integral side wall or apron which has a double thickness, with the inner wall of the apron having its free edge turned into engagement with the inner face of the outer wall so that no raw edge of metal will be visible and with the inner wall carrying a continuous, uninterrupted thread formation.

It is a still further object of the invention to provide apparatus for threading the interior side wall of a closure cap which is characterized by a double side wall or apron so as to provide a continuous uninterrupted thread formation for screw engagement with a cooperating thread on the mouth of a receptacle.

It is another object of the invention to provide a threading die of the type which comprises radially expan- 3,382,699 Patented May 14, 1968 sible die segments mounted on a support which enables the free ends thereof to be disposed in a cap forming shell for expansion into thread shaping engagement with the inside wall of the cap shell and having peripheral grooves in which an axially expansible wire spring member is seated so that when the die segments are expanded radially the spring member bridges the gaps between the die segments and forms, upon engagement with the shell wall, an uninterrupted thread.

These and other objects and advantages of the invention will be apparent from a consideration of the method and the several forms of the apparatus hereinafter described and illustrated in the drawings wherein:

FIGURE 1 is a vertical section through the axis of a cap threading head which incorporates a threading die embodying the principal features of the invention;

FIGURE 2 is a vertical section taken as in FIGURE 1 with the threading die in cap engaging position;

FIGURE 3 is a cross section taken on the line 33 of FIGURE 1;

FIGURE 4 is a cross section taken on the line 4-4 of FIGURE 1;

FIGURE 5 is a fragmentary vertical section taken on the line 5-5 of'FIGURE 4;

FIGURE 6 is a cross section taken on the line 66 of FIGURE 5;

FIGURE 7 is a partial side elevation showing the lowermost end of the threading die;

FIGURE 8 is a partial section through a cap blank as initially prepared prior to any thread forming operations;

FIGURE 9 is a fragmentary cross section similar to FIGURE 7 of a cap blank having the marginal portions of the skirt folded into double wall formation;

FIGURE 10 is a fragmentary cross section, similar to FIGURE 7, with the threading operations completed;

FIGURE 11 is a partial side elevation, to an enlarged scale, showing the lowermost end of a die for threading caps so as to provide multiple start thread formations;

FIGURE 12 is a cross section taken on the line 12--12 of FIGURE 11;

FIGURE 13 is a fragmentary vertical section taken through a shoe on the right side of FIGURE 11; and

FIGURE 14 is a fragmentary cross section illustrating a modified form of die for the multiple start thread formations.

The thread forming apparatus or assembly 10, which is illustrated in FIGURES 1 to 7 of the drawings, constitutes a portion only of a machine for forming caps which are characterized by a single start or single lead screw thread. The thread forming apparatus 10 is mounted on a stationary frame 11 above a traveling chuck holder 12, the latter being supported in a suitable manner so as to move into position beneath the threading apparatus 10 with a cap 14 in partially formed condition seated in a chuck 15 mounted therein. The chuck holder 12, in one type of machine, is moved successively through a series of work stations where successive operations are performed on the cap 14. The chuck 15, in which the cap is received as shown in FIGURE 1, is mounted for vertical sliding movement in the holder 12 and is normally provided with a knock-out pad 16 disposed on the upper end of a vertically sliding stem 17 which may be reciprocated vertically, relative to the chuck 15, by an appropriate r cam (not shown). The pad 16 includes a permanent magnet 18 or other suitable holding means for holding the cap 14 properly seated in the pocket 19 provided therefor in the chuck 15 when the knockout pad 16 is in retracted position as shown in FIGURES 1 and 2.

The cap member 14 is initially formed or shaped from a single blank into the form shown in FIGURE 8 to pro- 3 vide a top forming wall which may be indented as indicated at 21 and a depending skirt or rim 22, the cap being shown in inverted position in FIGURES 8 to 10. Preparatory to the formation of the thread the skirt 22 has its marginal portions inturned or reversely bent to provide an inner wall section 23 and an outer finished wall 24. The two walls 23 and 24 are separated or spaced a predetermined amount with a smooth rounded connecting lower edge 25 and with the raw edge 26 of the skirt curved into abutting engagement with the inner surface of the outer wall 24 as indicated in FIGURE 9. This closes off the space between the two Walls 23 and 24 and prevents entry therein of any foreign matter or of any of the contents of the receptacle on which the cap may be subsequently employed as a closure.

The cap 14 in the partially formed condition shown in FIGURE 8 may be seated in the chuck 15 and the operation on the skirt 22 required to provide the thread receiving inner wall 23 performed at a work station preceding the station where the threads are formed therein by the threading apparatus 10. The partially formed cap 14 is presented to the threading apparatus 10 in the condition shown in FIGURES l and 9.

The thread forming apparatus or assembly 10 comprises a holder 30 which is mounted in fixed position in a downwardly opening recess 31 in the stationary frame 11. The holder 30 has a top portion 32 of reduced cross section which is externally threaded for engagement therewith of an adjusting nut 33 which is adapted to be clamped on the stationary frame 11 by the clamp member 34, the latter being held in final position by cap screws 34'. A thread forming element 35 is mounted at the lower end of the assembly 10 and is in the form of a spiral spring which is seated in a spiral groove 36 in the outside surfaces of four expandible or radially slidable shoes 38. Each shoe 38 is mounted in a radially extending slot or recess 40 in the bottom end portion 41 of a body forming housing or holder member 42. The recesses 40 extend radially from the vertical axis of the body member or housing 42 and each of the shoes 38 is urged in an inward direction towards the vertical axis by a compression spring 43 having its outer end abutting an outer wall forming section 44 of the body member 42 which depends at the outer periphery of the slot 40. The inner end of the spring 43 is seated in a pocket provided therefor by an outwardly opening, radially extending bore 45 in the shoe 38. The shoes 38 are each adapted to have a limited amount of movement in the slots 40. They are held against movement in an axial direction by a centering plate 46 secured on the bottom end of the assembly by four cap screws 47 (FIGURES 5 and 6) which extend through elongate slots 48 formed between the confronting vertical faces of the shoes 38, the latter constituting in effect four segments of a tubular section. Each of the shoes 38 has its inner face cut away at 49 to provide clearance for movement of the lower end of a vertically disposed expander rod 50 between the oppositely disposed shoes 38. The lowermost portion of each inner face is beveled at 51 and the lower end of the expander rod has a complementary bevel 52 for wedge engagement with the beveled surface 51 on each of the shoes 38 so as to force the shoes 38 radially outwardly to expand the threading element 35 when the body member 42 and its associated shoes 38 are moved vertically to engage the surfaces 51 with the surface 52 on the expander rod 50. The expander rod 50 is received at its lower end in sliding relation in an axial bore 53 in the body member 42 and the latter is mounted for vertical reciprocation in a sleeve 54 which is secured at the lower end of an intermediate bore 55 in the holder member 30 and has an associated O-ring 56 for sealing off the bottom of an adjacent bore 57 of somewhat smaller diameter which houses a compression spring 58. The spring 58 is seated at its lower end against a stop ring 60 secured by cap screws 61 on the upper end of the body member 42. At its upper end the spring 53 is seated against a shoulder 62 formed at the junction of the bore 57 and an upper bore 63 of smaller diameter. The bore 63 is threaded to receive the threaded upper end portion 64 of expander rod 50 and a jam nut 65 is provided at its upper end for holding the rod 50 in fixed position in the holder member 30. The holder member 30 has a lower section 66 of greater diameter than the main portion 67 with an internal bore 68 opening downwardly in which a bushing 70 is retained by cap plate 71 and associated clamping bolts 72. The bushing 70 has a bore 73 in which the head forming lower end portion 41 of the body member 42 is slidably received.

In operation, the cap 14 with the rim 22 having its marginal portion curled inwardly to form the inner side wall 23 of the cap shell 14 is carried by the chuck 15 into position below the assembly 10 and thereafter the chuck 15 is elevated to seat the lower end portion 41 of the body member 42 in the cap 14. Continued upward movement of the chuck 15 engages the beveled lower end 52 of the expander rod 50 with the beveled surfaces 51 of the segments or shoes 33 and expands the thread forming spring 35 into engagement with the wall 23 with suflicient pressure exerted to form the threads in the Wall 23 which will match the threads on the receptacle when the cap is placed thereon. The spring member 35 bridges the gaps between the radially expanded segments 38 and insures that the thread thus formed is continuous. The chuck 15 is retracted after the thread is formed which allows the spring member 35 to contract and along with the springs 43 force the segments 38 to contracted position, allowing the spring member 35 to be withdrawn from the cap 14.

The method and apparatus are particularly adapted for use in connection with the threading of closure caps of the one piece type illustrated and described. However, the method and apparatus may be employed as well in connection with the threading of cap structures which are formed in more than one piece, for example, jar caps comprising a threaded clamping ring portion and a cooperating separate top closure panel. Also, the method and apparatus are not limited to the fabrication of bottle and jar caps but thread formations may be formed according to the method and by means of the apparatus on any thin walled annular member made of pressure deformable material which is capable of receiving the thread for mation.

Although the aforementioned apparatus may be considered the preferred embodiment of the invention, when it is desired to fabricate a cap with multiple start thread formations, the apparatus may take the form shown in FIGURES 11 to 14. The assembly for forming multiple start threads is constructed in the same manner as the single start thread forming assembly 10 except for the thread forming elements which comprise, in the form illustrated, four separate lengths or sections 111, 112, 113 and 114 of spiral spring instead of the single length 35 which is employed in assembly 10. The four spiral spring members 111, 112, 113 and 114 are seated in relatively shallow spiral recesses or grooves 115, 116, 117 and 118 in the peripheral surfaces of four radially slidable shoes 120, 121, 122 and 123 which are supported for radial movement in radially extending slots in the bottom end of a body member or housing 124 in the same manner as the radially slidable shoes 38, with the housing 124 being mounted in the same manner as the housing 42 and having associated elements of the same character for radially moving the shoes 120, 121, 122 and 123 outwardly and inwardly relative to the vertical axis of the housing 124. Each spring member 111, 112, 113 and 114 has a length sufficient to extend a circumferential distance somewhat greater than 180 as viewed in FIGURE 12 so as to remain seated in the associated groove. Each of the grooves 115, 116, 117 and 118 terminates at its lower end at a vertical edge of one of the shoes 120, 121, 122 and 123, as illustrated at 125 in FIGURE 11, in connection with groove 115 so that the lower end of the spring member in each groove is restrained against movement in the axial direction which would permit it to be screwed off the end of the tool. The grooves 115, 116, 117 and 118 have a length which is somewhat greater than the associated spring section so as to insure that the spring is free to expand and retract while it remains seated in the groove. The lower end of each spring may be anchored as illustrated in FIGURE 14 where the spring 111' has an inwardly turned bottom end 126 which is seated in a bore 127 in the associated supporting shoe. This leaves the other end free to move in the associated groove 115' when the spring expands or contracts due to radial movement of the supporting shoes.

While particular materials and specific details of construction are referred to in describing the foregoing method and the forms of the apparatus illustrated, it will be understood that other materials and equivalent structural details may be resorted to within the spirit of the invention.

I claim:

1. In a machine for threading a closure cap which is characterized by a top forming panel and a depending peripheral skirt with the skirt having a thread receiving inner wall formed by inwardly bending an integral marginal portion thereof, a thread forming assembly comprising a housing member having an end face with a plurality of outwardly opening, radially extending recesses therein, a series of radially movable shoes mounted in said recesses, said shoes being formed with portions extending beyond the end face of the housing and providing circumferential faces adjoining each other and cooperating to form a substantially cylindrical expandable surface, and a continuous thread forming element carried on said shoe faces which is in the form of a coiled spring member and which is mounted thereon so that when said extending portions of the shoes are placed Within a closure cap and then moved outwardly the thread forming element is expanded in a radial direction and the outer surface is forced with sufiicient pressure into engagement with the inner wall of the cap to shape therein a continuous screw thread.

2. In a machine for threading a partially formed metal closure cap which is characterized by a top wall forming panel and a depending peripheral skirt having an outer wall section and a thread receiving inner wall section joined at its outer edge with the outer edge of the outer wall section, a thread forming tool comprising a body forming member having an end face with radially extending end recesses opening in the direction of the axis thereof, a plurality of shoes movably mounted in the radially extending recesses with portions thereof projecting outwardly of the body member so as to provide a support in the form of a cylinder having an outer face with a spiral recess therein and a thread producing element in the form of a coiled spring member seated in said spiral recess, and means for moving said shoes in a radial direction so as to expand said coiled spring member when said coiled spring member is disposed within a partially formed cap so as to engage in a radial direction and the outer surface is the inner wall section of the cap and form therein a continuous uninterrupted thread.

3. Apparatus for forming threads in the inner wall of the skirt of a closure cap which is characterized by a top forming panel and a double walled skirt depending from the periphery thereof which comprises a cylindrical body forming member with a mounting head at one end of an axial bore which bore is adapted to slidingly receive an expander rod having a wedge shaped end adapt-- ed to project into the mounting head, radial slots in said mounting head which extend outwardly of the axial bore, laterally displaceable segmental shoes mounted in said slots and spring members urging said segmental shoes in the direction of the axial bore, said segmental shoes having peripheral surfaces extending outwardly of said mounting head with a continuous spiral groove in said peripheral surfaces and asection of .a coil spring seated in said spiral groove, said spring being expandable laterally upon engagement of the innermost surfaces of the shoes with the wedge shaped end of said expander rod thereby bridging the space between the shoes and engaging with the inner wall of the closure cap skirt so as to form a continuous thread therein.

4. Apparatus for forming threads in the inner surface of the side wall of a metal closure cap which is char acterized by a top forming panel and a double walled skirt depending from the periphery thereof, which apparatus comprises a cylindrical body member having an axial bore which is adapted to slidingly receive an expander rod with a beveled end, said body member having radial slots in the one end thereof which extend outwardly of the axial bore, laterally displaceable segmental shoes mounted in said slots and means normally urging said segmental shoes in the direction of the axial bore, said segmental shoes having peripheral surfaces extending outwardly of said body member and a section of a coiled spring seated on said peripheral surfaces, said spring being expandable laterally upon engagement of the innermost surfaces of the shoes by the beveled end of said expand-er rod when the apparatus is positioned with said peripheral surfaces opposite the inner wall of a cap skirt and the expander rod is moved toward said shoes whereby said spring is forced into thread forming engagement with said inner wall, with the spring spanning the space between the peripheral surfaces of the shoes so as to from an uninterrupted thread formation in the skirt wall.

5. Apparatus for forming threads in the inner wall of the skirt of a closure cap which is characterized by atop forming panel and a double walled skirt depending from the periphery thereof, said apparatus comprising a cylindrical body member with an axial bore which receives therein a slidable expander rod having a beveled end, said body member having radial slots in one end thereof which extend outwardly from said axial bore, radially slidable segmental shoes mounted in said slots and resilient means normally urging said segmental shoes in the direction of said axial bore, said segmental shoes having peripheral surfaces facing outwardly of said axial bore with a spiral groove in said peripheral surfaces and a thread forming coiled spring member seated in said spiral groove, said spring member being expandable laterally of said axial bore upon engagement of the innermost surfaces of the shoes by the beveled end of said expander rod whereby a cap may be positioned on the end of said body member so that the skirt encompasses said spring member, and said expander rod may be moved toward said shoes to force said spring member into thread forming engagement with the inner Wall of the skirt, with the spring member spanning the space between the outer surfaces of the shoes.

6. In a machine for threading a metal closure cap which is characterized by a top wall forming panel and a depending peripheral skirt having a thread accommodating inner wall portion joined at its outer margin with the edge of an outer wall portion of the skirt, a thread forming device comprising a body member having an axial bore and an end with radially extending guideway forming recesses opening in the direction of said axial bore, a plurality of shoes movably mounted in the radially extending recesses with portions thereof projecting outwardly at the end of the body member so as to provide a support in the form of a segmented cylinder with the outer cylindrical face having a spiral recess and a continuous thread producing element in the formof a section of coiled spring seated in said spiral recess, and means for moving said shoes radially so as to expand said thread producing element laterally with said thread producing element bridging the gaps between said shoes when they are expanded whereby said thread producing element may be disposed within the skirt of a closure cap and expanded so as to engage said element with the inner wall of the cap and form therein a continuous thread.

7. Apparatus for forming threads in a thin walled annular member made of deformable material, which apparatus comprises a thread formin tool having a body member with an end face in which there are a plurality of radially extending recesses opening in the direction of the axis thereof, a plurality of shoe movably mounted in the radially extending recesses with portions thereof projecting outwardly of the body member so as to provide a cylindrical supporting surface with a spiral recess in the outer face thereof and .a thread producing element in the form of a coiled spring member seated in said spiral recess, and mean for moving said shoes in a radial direction so as to expand said thread producing element whereby when said thread producing element is expanded within said annular member sufficiently to engage said thread producing element with the inner wall of said annular member a continuous thread is formed therein.

8. Apparatus for forming threads in a thin Walled annular member made of deformable material, which apparatus comp-rises a thread forming tool having a body member with an end face in which there are a plurality of radially extending recesses opening in the direction of the axis thereof, a plurality of shoes movably mounted in the radially extending recesses with portions thereof projecting outwardly of the body member so as to provide a cylindrical supporting surface and spiral grooves in said cylindrical supporting surface, thread producing elements seated in said spiral grooves which are in the form of coiled spring members, and means for moving said shoes radially so as to expand the coiled spring members, when positioned within said annular member, sufiiciently to engage said coiled spring members with the inner Wall of said annular member and form continuous uninterrupted threads therein.

9. Apparatus for forming multiple start threads in a thin walled annular member made of deformable material, which apparatus comprises a thread forming tool having a body member with an end face and a plurality of shoes mounted therein for radial movement outwardly of the axis thereof, portions of said shoes extending in a radial direction outwardly of the body member and providing a cylindrical supporting surface adjacent said end face, said cylindrical surface having a plurality of relatively shallow spiral recesses in the outer face thereof and a length of coiled spring seated in each of said recesses so that a portion thereof projects beyond the outer face of said cylindrical surface, and means for moving said shoes to expand the coiled springs sufficiently, when positioned within said annular member, to engage the projecting portions of said coiled springs with the inner wall of said annular member and form threads therein, said coiled springs having a circumferential dimension greater than the corresponding dimension of a single shoe and bridging the gap between a shoe and an adjoining shoe which results when the shoes are expanded whereby to form threads which are uninterrupted.

10. A method of threading a closure member which is adapted for use as a cap on the threaded mouth of a jar or the like which comprises positioning a coiled spring member having a peripheral contour corresponding to the contour of the thread desired within a cap shell which has a side wall forming skirt so that the spring member is encompassed by the skirt and the innermost surface of the skirt confronts the peripheral surface of the spring member, restraining the spring member against extension in an axial direction, and expanding the spring member radially of its axis so that it engages the innermost surface of the skirt with sufficient force to form a continuous uninterrupted thread in said cap skirt with the thread contour corresponding to the peri heral surface of the spring member.

11. A method of threading a thin Walled annular member made of pressure deformable material which comprises positioning a coiled spring member having a peripheral contour corresponding to the contour of the thread desired within said annular member so that the spring member is encompassed by said annular member and the innermost surface of said annular member confronts the peripheral surface of the spring member, and expanding the spring member radially of its axis so that it engages the innermost surface of said annular member with sufiiicent force to form in said confronting surface a continuous uninterrupted thread having a thread contour corresponding to the peripheral surface of the spring member.

12. A method of threading a closure cap for a jar or similar member which is in the form of a shell having a top forming panel and a depending skirt with the bottom margin turned inwardly to provide spaced inner and outer Walls, said method comprising the step of positioning in the shell a spiral spring member so that said spring member is encompassed by the inner wall of the skirt, said spring member having an outer surface with a contour corresponding to the desired thread contour, expanding the spring member and bringing the peripheral surface thereof into engagement with the inner surface of the inner wall of the skirt with sufficient force to form in said surface a continuous, uninterrupted thread formation, and contracting the spring member to enable the closure member to be disengaged therefrom.

13. A method of threading a closure cap for a jar or similar member which is in the form of a shell having a top forming panel and a depending skirt with the bottom margin of the skirt turned inwardly to provide an inner wall for receiving the thread formation, said method comprising the step of positioning in the shell a spiral spring member having an outer surface with a contour corresponding to the desired thread contour, expanding the spring member so as to engage the inner surface of the inner wall of the skirt with sufficient pressure to form in said inner wall the desired thread formation, and contracting the spring member so as to permit the closure member to be disengaged therefrom.

References Cited UNITED STATES PATENTS 1,420,875 6/1922 Smith 1l312l 1,900,880 3/1933 Kramer 1l3--l X 2,045,602 -6/1936 Huntsman 1131 2,421,935 6/1947 Gosnell 72393 X 2,626,581 1/1953 Almgren et al. 72399 X 2,350,410 6/1944 Murphy 72-395 3,322,086 5/1967 Pentesco 1131 CHARLES W. LANHAM, Primary Examiner.

E. SUTTON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,382,699 May 14, 1968 Herman A. Seeman It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, lines 60 and 61, "in a radial direction and the outer surface is" should read the outer portions of the spring member with Signed and sealed this 30th day of September 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

